Conventionally, an A/D (analog/digital) converter converting an analog signal to a digital signal is used in various apparatuses. In general, the A/D converter requires high precision and low power consumption. An example of an A/D converter that achieves both high precision and low power consumption is an incremental delta-sigma A/D converter.
FIG. 1 is a block diagram illustrating an incremental delta-sigma A/D converter of Patent Literature (PTL) 1. The incremental delta-sigma A/D converter includes a sample hold (SH) circuit 1, a reset signal generator 2, a delta-sigma modulator 3, and a digital operation unit 4. The delta-sigma modulator 3 includes an analog integrator 12 having L (>=1) stages, a quantizer 13, a D/A converter (DAC) 14, and an adder 11. The reset signal generator 2 is configured to reset the analog integrator 12 and a digital integrator (not illustrated in the drawing) of the digital operation unit 4 before converting an analog signal to a digital signal. The incremental delta-sigma A/D converter is different from an ordinary delta-sigma A/D converter in that it is characterized by including the reset signal generator 2.